Question

I am currently working on a some C code, very new to C, so apologize if this is a bit basic or a stupid question.

I have the following code which is executed within a thread using pthread_create().

if (ps.status == completed)
        {
            LOG(LOG_AUDIO, "evsafewait_sm_play_tone:\tPlay tone complete");
            if (e2)
            {
                LOG(LOG_MUST, "Failed to free tone event. Result: %i", e2);
            }

            pccb->playToneComplete = 1;
            LOG(LOG_AUDIO, "Detatching thread ID %x", manageToneParms->toneManagerThread);
            //pthread_detach(manageToneParms->toneManagerThread);

            int retVal;
            pthread_exit(&retVal);
            LOG(LOG_AUDIO, "THREAD TERMINATED WITH RESULT %i", retVal);
            LOG(LOG_AUDIO, "Freeing memory");

            free(manageToneParms->playToneParms);
            free(manageToneParms);
            return 0;
        }  

Before the structures are free and the method returns I am trying to exit the thread using pthread_exit() but when this is called, everything below it is skipped, no errors are displayed, as far as I can see anyway.

I have tried debugging it with GDB and when pthread_exit() is called the next thing it prints out is siglongjmp, I have no idea what this is, I don’t believe it’s in the C code, at least not in the changes that I have been making to it.

How can I exit this thread? I’ve also tried pthread_exit(NULL) and pthread_kill(threadID, SIGKILL) but then this kills the whole program not just the thread.

Answer 1

pthread_exit() returns from the thread at the point of the call. Any code after pthread_exit() will not be executed.

You should be sure to release any memory allocated in the thread before calling pthread_exit().

Have you tried something like this:?

int retVal;

/* free resources -- make sure all resources allocated in thread 
   function are released 
*/
free(manageToneParms->playToneParms);
free(manageToneParms);

LOG(LOG_AUDIO, "THREAD TERMINATED WITH RESULT %i", retVal);
LOG(LOG_AUDIO, "Freeing memory");
pthread_exit(&retVal);